Eine weitere Synthese von (±)‐Lycopodin

Schumann, D.; Müller, Hans-Jürgen; Naumann, A.

doi:10.1002/jlac.198219820910

Cited by 39 publications

(12 citation statements)

References 9 publications

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“…[94][95][96][97] Schumann used a classical Mannich strategy to access racemic lycodine, a-obscurine and N-acetylabellidine (Scheme 15). [98][99][100] The mechanism of the key double Mannich reaction cascade was further explored almost 30 years later by Sarpong. 94 He used the same cascade as an opening sequence in an asymmetric synthesis of enantiomerically pure (+)-complanadine A, a lycodine dimer, which was shown to enhance expression of nerve growth factor in human cells.…”

Section: Methodsmentioning

confidence: 99%

Synthetic approaches towards alkaloids bearing α-tertiary amines

et al. 2016

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Alkaloids account for some of the most beautiful and biologically active natural products. Although they are usually classified along biosynthetic criteria, they can also be categorized according to certain structural motifs. Amongst these, the α-tertiary amine (ATA), i.e. a tetrasubstituted carbon atom surrounded by three carbons and one nitrogen, is particularly interesting. A limited number of methods have been described to access this functional group and fewer still are commonly used in synthesis. Herein, we review some approaches to asymmetrically access ATAs and provide an overview of alkaloid total syntheses where those have been employed.

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Section: Methodsmentioning

confidence: 99%

Synthetic approaches towards alkaloids bearing α-tertiary amines

et al. 2016

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“…In the same year of Heathcock's landmark work on the Lycopodium alkaloids, Schumann's group also reported a total synthesis of lycopodine (1) (Scheme 16). 40 This approach has similarities to Heathcock's approach: it started from the same starting material, 5-methyl-1,3-cyclohexadione (97), and had many of the same key steps. Schumann converted diketone 97 into bicyclic imine 100 in five steps.…”

Section: Account Syn Lettmentioning

confidence: 99%

“…The use of 3-iodopropanol (173) was important here, as 3-bromopropanol is known to give a low yield in a similar alkylation reaction. 40 Next, the tandem Oppenauer oxidation/intramolecular aldol condensation produced the desired enone 175 in 71% yield. The use of freshly prepared t BuOK and freshly distilled benzene were necessary to achieve a reproducibly high yield in this transformation.…”

Section: Scheme 26 Synthesis Of the Tricyclic Skeleton Through Mannich Reactionmentioning

confidence: 99%

Lycopodium Alkaloids: An Intramolecular Michael Reaction Approach

Saha¹,

Carter²

2017

Synlett

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The Lycopodium alkaloids possess a rich history that has captured the attention of synthetic chemists across the globe. This large family consists of over 250 known natural products with diverse structural features and noteworthy biological activity. Herein, we interweave the synthetic accomplishments by others in the field with our own unified strategy to accessing multiple subfamilies of the Lycopodium alkaloids. This discussion includes lycopodine, the C10-hydroxy Lycopodium alkaloids (10-hydroxylycopodine, deacetylpaniculine and paniculine), pelletierine, cermizine D, fastigiatine, himeradine A, clavolonine and 7-hydroxylycopodine. A unifying feature of much of the work discussed within this account is the use of intramolecular Michael additions to construct key ring systems within the Lycopodium alkaloids. Examples include the use of an intramolecular keto-sulfone Michael reaction and an intramolecular heteroatom Michael reaction.1 General Background on Lycopodium Alkaloids2 Development of a Strategy for Lycopodium Alkaloids2.1 Generalized Strategy2.2 Known Syntheses of C10-Functionalized Lycopodium Alkaloids3 Quinolizidine-Type Alkaloids3.1 Background3.2 Development of the Heteroatom Michael Reaction3.3 Synthesis of the Core Lycopodine Building Block: Pelletierine3.4 Total Synthesis of Cermizine D3.5 Synthesis of the Eastern Half of Himeradine A4 Lycopodine-Type Alkaloids4.1 Total Syntheses of Lycopodine4.1.1 Earlier Racemic Syntheses4.1.2 Approach Toward the Tricyclic Skeleton of Lycopodine: Intramolecular Mannich4.1.3 Enantioselective Total Syntheses of Lycopodine4.2 Total Syntheses of Clavolonine (8-Hydroxylycopodine)4.3 Total Synthesis of 7-Hydroxylycopodine4.4 Synthetic Route for 10-Hydroxy Lycopodium Alkaloids4.4.1 Background4.4.2 Total Syntheses4.4.3 Impact of the C10-Stereochemistry5 Conclusion

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“…Due to the propensity of 2-(3-aminopropyl)cyclohex-2-enones to undergo 1,2-rather than 1,4-addition, [35] we proposed that removal of the tosyl group from a cyclized compound and a simple isomerization at C-4a would be the most effective way to access the desired trans stereochemistry. Due to the propensity of 2-(3-aminopropyl)cyclohex-2-enones to undergo 1,2-rather than 1,4-addition, [35] we proposed that removal of the tosyl group from a cyclized compound and a simple isomerization at C-4a would be the most effective way to access the desired trans stereochemistry.…”

Section: Wwwchemeurjorgmentioning

confidence: 99%

Synthetic and DFT Studies Towards a Unified Approach to Phlegmarine Alkaloids: Aza‐Michael Intramolecular Processes Leading to 5‐Oxodecahydroquinolines

Bradshaw

Luque‐Corredera

Saborit

et al. 2013

Chemistry A European J

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A diastereoselective synthesis of cis-5-oxodecahydroquinolines is described in which three stereocenters are generated in a one-pot reaction. The reaction involves a lithium hydroxide-promoted Robinson annulation/intramolecular aza-Michael domino process from an achiral acyclic tosylamine-tethered β-keto ester. The development and scope of this reaction was facilitated through the use of DFT-based mechanistic studies, which enabled the observed diastereodivergent course of the azacyclization to be rationalized. The varying stereochemistry and stability of the resulting decahydroquinolines was found to depend on whether a β-keto ester or ketone were embedded in the substrates undergoing aminocyclization. This synthetic approach gave access not only to both diastereomeric cis-decahydroquinolines from the same precursor, but also to the corresponding trans isomers, through an epimerization processes of the corresponding N-unsubstituted cis-5-oxodecahydroquinolines. The described methodology provides advanced building-blocks with the three relative stereochemistries required for the total synthesis of phlegmarine alkaloids.

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Eine weitere Synthese von (±)‐Lycopodin

Cited by 39 publications

References 9 publications

Synthetic approaches towards alkaloids bearing α-tertiary amines

Synthetic approaches towards alkaloids bearing α-tertiary amines

Lycopodium Alkaloids: An Intramolecular Michael Reaction Approach

Synthetic and DFT Studies Towards a Unified Approach to Phlegmarine Alkaloids: Aza‐Michael Intramolecular Processes Leading to 5‐Oxodecahydroquinolines

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